36 Studies on Water Drinking [Oct. 



bacterial nitrogen in fecal nitrogen, were less in the period of 

 copiotis water-ingestion than in the "moderate water" period. 

 Also, the values for these forms of nitrogen were less in the final 

 period than in the preliminary period. Thus, data obtained from 

 two subjects, while differing in detail, show the same general fea- 

 tures, moderate amounts of water producing desirable results, while 

 larger amounts have an augmented effect for the better. 



General discussion. Bacteria-excretion. As Ehrenpfordt 

 (13) has shown, the different values for bacterial nitrogen are 

 caused by a diversity in the centrifugation procedure. With a high 

 rate of speed the lighter bacterial substances are thrown out of Sus- 

 pension, while a slower rate of speed will cause more of these par- 

 ticles to remain in Suspension during the course of a given length of 

 time. Thus, it would appear to be almost impossible to stop at just 

 the moment when all the non-bacterial substances have been removed 

 and all of the bacteria are still in Suspension. Ehrenpfordt has 

 further stated that entirely comparable and trustworthy results are 

 obtained by any given worker, using the same technic throughout. 

 The absolute values are not so important as are the relations be- 

 tween values of different parts of an experiment obtained by a single 

 experimenter. 



Harris (12) as the result of recent experiments wrote as fol- 

 lows regarding the centrifugation procedure for bacteria deter- 

 mination: "I am of the opinion that if workers in this country, at 

 least, are to continue using the method, some endeavor ought to be 

 made to unify or standardize the technic; otherwise interlabora- 

 tory results cannot be considered comparable." 



Siibjcct V. Thirty-two stools were examined and analyzed 

 for fecal bacteria-nitrogen, the method described by Mattill and 

 Hawk (11) being employed with modifications as stated above. 

 The percent of dry bacteria in the dry feces was found to vary 

 from 27.78 percent to 46.64 percent, with an average of 33.36 per- 

 cent. The ratio of bacterial nitrogen to fecal nitrogen varied from 

 53.12 percent to 76.14 percent, the average being 58.82 percent. 

 The average daily excretion of bacterial dry substance was 7.232 gm. 



Suhject C. Thirty stools were examined and produced the 

 foUowing results: 26.51 percent of dry bacteria were found in the 



